Romney took the same position as governor of Massachusetts, an office he held from 2003 to 2007, and as a candidate for president in 2008.

As Yahoo News reported last month, Romney's support for a minimum wage raise—something Democrats have been pushing for and Republicans have generally opposed—provoked a furor on the right. "All it does is give the base another reason to be unenthusiastic about him," conservative publishing magnate Steve Forbes, who made his own bids for the GOP nomination in 1996 and 2000, told us.

The Wall Street Journal editorial page, the Club for Growth and several other major conservative players also slammed Romney's stance, arguing that raising the minimum wage makes small businesses less likely to hire workers. A 1993 study by the economists Alan Krueger—now President Barack Obama's top economic adviser—and David Card found no such effect.

None of Romney's rivals for the nomination support raising the minimum wage, and one of them, Rep. Ron Paul, has said the concept should be scrapped.

Romney's new stance may help him consolidate his position on the right, but could hurt him in November. According to Gallup, public support for raising the minimum wage has consistently exceeded 75 percent over the past two decades.